This invention relates to fetal probes and, more particularly to a connector assembly for coupling a fetal electrode to a remote monitoring device.
One type of fetal probe comprises a bipolar fetal electrode commonly used to monitor fetal heart rate during birth. This type of probe consists of a spiral fetal electrode mounted on a carrier along with an electrically isolated maternal electrode. A twisted pair of wires are connected at one end to the fetal and maternal electrodes and at their opposite ends to a connector. One such connector consists of a pair of axially spaced electrodes which are electrically isolated and each of which is connected to one of the wires. The connector is adapted to be coupled to a socket having axially spaced connectors which, in turn, are coupled by a cable to the monitor.
Initially, the twisted pair of conductors and the connector are disposed in a hollow drive tube. The end of the drive tube is inserted into the mother""s cervix until the forward end contacts the fetus. The role of the drive tube is to push forwardly until the spiral fetal electrode at the forward end makes contact with the fetal epidermis. The drive tube is then rotated to screw the spiral electrode into the fetal epidermis. The drive tube is then slid over the wires and the connector while the bipolar electrodes and the twisted pair of wires remain within the mother and connected to the fetus. The removal of prior art tubes required the dexterous manipulation of the drive tube which were designed to maintain a grip on the twisted pair so as to insure that the drive tube is engaged at the distal end. Defeating the grip tended to be cumbersome. In these prior art connectors, the connector at the other end of the twisted pair of conductors is exposed. Such exposed electrodes could soil or contact energy sources and tended to be disconcerting to the patient or her partner.
In one type of assembly the socket for receiving the connector is mounted on a support or circuit board which electrically connects to a plate mounted on the mother""s leg by an adhesive pad and provides a reference for the fetal and maternal electrodes. The support or circuit board connects to the leg plate by a snap electrical connector. Such snap connectors do not uniformly provide a distinct snap to indicate that good electrical contact has been achieved. In addition, the forces necessary to couple and disconnect the contacts are not consistent. As a result, medical personnel may not be aware should a good electrical connection not be achieved.
In general terms, one aspect of the invention comprises a fetal electrode assembly for use in monitoring fetal heart rate, the assembly being used in conjunction with a fetal monitor coupling device. The assembly comprises a fetal electrode and a maternal electrode mounted on an insulating holder, a connector configured to be received in an opening in the coupling device and having first and second tubular contacts separated and electrically isolated from each other and positioned to make electrical contact with complementary contact members in the coupling device, the first tubular contract having a larger diameter than the second tubular contact. An insulated pair of elongated flexible wires electrically connects a respective one of the contacts to a respective one of the fetal and maternal electrodes and an elongate tubular sheath covers the connector and is configured to be received in the open end. The sheath has a first opened end extending over and receiving the ends of the pair of flexible wires and an opposite open end spaced from each of the electrodes so that a gap is formed between the electrodes and the open end of the sheath.
Another aspect of the invention comprises the combination of a fetal electrode assembly and a fetal monitor coupling device for use in monitoring fetal heart rate. The assembly comprises a fetal electrode and a maternal electrode secured to an insulating holder, a connector configured to be received in an opening in the coupling device housing and having at least two contacts separated and electrically isolated from each other, an insulated pair of elongate flexible wires electrically connecting a respective one of the contacts to a respective one of said fetal and maternal electrodes. The coupling device includes third and fourth contacts disposed for receiving the first and second contacts, respectively, the third contact comprising a tubular member coaxial with and having one end opposed to an opening in the coupling device, and the fourth contact comprises an elongate member having one end disposed within the third contact member and electrically isolated therefrom, the other end of the fourth contact extending from the one end of the third contact and toward the opening.
According to another aspect, the invention comprises the combination of a fetal electrode assembly and a fetal monitor coupling device for use in monitoring fetal heart rate. The assembly comprises a fetal electrode and a maternal electrode mounted on an insulating holder, a connector configured to be received in an opening in the coupling device housing and having first and second contacts separated and electrically isolated from each other. Third and fourth contacts are disposed in the coupling device housing and are separated and electrically isolated from each other in an opposed relation to an opening in the housing, and positioned to make electrical contact with the first and second contacts respectively. An insulated pair of elongated flexible wires electrically connect a respective one of the first and second contact to a respective one of the fetal and maternal electrodes. The coupling device housing has a second opening for receiving a snap connector of an electrode and a fifth contact is disposed within the housing and includes a wire bent to define a pair of parallel spaced apart legs, one end of each of the legs being interconnected by a resilient loop section, the other ends of the legs being free. The legs are adapted to resiliently engage a snap connector. A support is disposed in the housing and a mounting member is engageable with a support in the housing and includes a cavity for receiving the fifth contact for mounting the fifth contact on the support, the support having conductors connected, respectively, to the third, fourth, and fifth contacts.
The invention provides a new and improved connector for bipolar electrodes which does not expose the patient to electrically energized objects. The invention also provide a new and improved clamp for the drive tube of a bipolar electrode and more particularly a quick release clamp for the drive tube of a bipolar electrode. Moreover, the invention includes a new and improved leg plate connector for bipolar electrodes which provides a more reassuring appearance to the patient and her partner and an audible or other more consistent indication that contact has been achieved.